1. Field of the Invention
The present invention relates to a ratchet tool, and more particularly to a ratchet tool including an improved structure having an increased driving torque.
2. Description of the Prior Art
Various kinds of typical ratchet tools have been developed and comprise a cartridge rotatably received in a head of a handle, and a pawl for engaging with the cartridge, in order to control and to determine the driving directions of the typical ratchet tools. Normally, the typical ratchet tools include a single pawl for engaging with the cartridge, such that the driving torque is limited and may not be increased.
For example, U.S. Pat. No. 6,044,731 to Hsieh discloses one of the typical ratchet tools including a pawl rotatably received in the head of the handle, and the pawl includes two end teeth for engaging with outer peripheral teeth provided on the cartridge, so as to control and to determine the driving directions of the typical ratchet tools.
Similarly, U.S. Pat. No. 6,138,532 to McCann discloses another typical ratchet tool including a number of inner peripheral teeth provided in the head of the handle, and a pawl rotatably received in the cartridge and having two end teeth for engaging with the inner peripheral teeth of the head of the handle, in order to control and to determine the driving directions of the typical ratchet tools.
However, the typical ratchet tools include a single pawl for engaging with outer peripheral teeth provided on the cartridge, or for engaging with the inner peripheral teeth of the head of the handle, and may thus have only one point contact between the pawl and the cartridge and the head, such that the driving torque of the typical ratchet tools is limited and may not be increased.
U.S. Pat. No. 6,205,891 to Huang et al., and U.S. Pat. No. 6,311,584 to Chu disclose two further typical ratchet tools each including a number of inner peripheral teeth provided in the head of the handle, and two pawls rotatably received in the cartridge and each having two end teeth for engaging with the inner peripheral teeth of the head of the handle, in order to control and to determine the driving directions of the typical ratchet tools.
The typical ratchet tools include two pawls for engaging with the inner peripheral teeth of the head of the handle. However, there will be only two point contacts provided between the pawl and the cartridge and the head, such that the driving torque of the typical ratchet tools is limited, and the driving connection between the cartridge and the head may not be stable. Normally, three point contacts may form a plan and may provide a stable driving connection between the cartridge and the head.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ratchet tools.